1. Field of the Invention
This invention relates to hinge devices and more particularly to a fold-away type hinge which may support a work surface such as a small work table in a horizontal in-use position and then allow the table to be rotated to a vertical position for storage.
2. Prior Art
Fold-away type hinging devices that allow a work surface to be rotated from a vertical storage area to a horizontal in use position are well known and have been in use for some time.
One early fold-away type hinge is set forth in U.S. Pat. No. 1,580,289. This hinge comprises a lower strut having an inner end pivotally attached to a vertical member. An outer end of the lower strut is formed with a slot and a lug shaped head with a locking point. This hinge further includes an upper strut defined by spaced apart sidewalls connected by a top wall. The top wall terminates short of an inner end of the upper strut. The lug shaped head of the lower strut is positioned between the sidewalls at the upper strut inner end. Then, a pin carried by these sidewalls is disposed in the lower strut slot to form a slideable pivot connection. An outer end of the upper strut is pivotally connected to an outer end of the shelf while an inner end of a shelf is hinged to a top of the vertical support.
When the shelf is in an in-use horizontal position, the shelf is supported by the struts. The struts are held in place by an interference fit between the lower strut lug locking point and the upper strut top wall. To lower the shelf to a vertical out-of-use position, the shelf is first raised allowing the locking point to release from the outer strut top wall. The shelf then may be lowered to a vertical position next to the support.
Another early fold-away type hinge device is disclosed in U.S. Pat. No. 1,658,771. This device includes a vertical support which may be attached to a back wall of a storage compartment. Pivotally connected respectively to a top and a bottom end of the vertical support are inner ends of an upper and a lower arm. Outer ends of these arms in turn are spaced apart and pivotally attached to a side of a wall table. When the table is positioned horizontally for use, the upper arm aligns with a side of the table while the lower arm is positioned on an angle to form a brace. Downward rotation of an outer end of the table is prevented by an interference fit between a stop member in the storage compartment and an upper side of an inner end of the table.
A still further hinge device allowing movement of a casement-type window between a vertical closed position and a horizontal open position in a window frame is disclosed in U.S. Pat. No. 3,497,909. This hinge comprises an upper and lower pivot arm. The upper arm has an inner end pivotally connected to a block slideably disposed in a slot in an upper portion of the frame. An outer end of the upper arm is pivotally connected to an upper portion of the window. Ends of the lower arm are pivotally connected to a lower portion of the frame and a lower end of the window respectively. When the window is opened, the lower arm rotates downward about its frame connection while the bottom end of the window swings up. The upper arm first in turn rotates downward about the block connection with the block then sliding downward in the frame slot so that the window may be positioned horizontally.